This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-330191, filed Nov. 19, 1999; and No. 11-330193, filed Nov. 19, 1999, the entire contents of which are incorporated herein by reference.
The present invention relates to a light scanning optical device including a scanning optical system, and an endoscope using the same.
In a conventional electronic endoscope, the illumination light emitted from a light source is guided to a subject by a light guide to illuminate it. The reflected light from the subject passes through an objective lens is imaged by an imaging lens, and is subject to photoelectrical conversion by an image sensor such as a charge coupled device (CCD) disposed on its image plane. A signal from the CCD is imaged by a signal processor, and its image is displayed on a monitor, for example.
The CCD, which is employed in a conventional electronic endoscope, is expensive. In particular, a miniaturized CCD is very expensive because it requires an advanced manufacturing process. This causes an increased cost of an optical device such as, for example, an endoscope.
In addition, there is a restriction that the resolution of an obtained image almost depends on the resolution of the CCD. In the CCD, an image is outputted in units of pixels. With advancement of the manufacturing process, although the size of the pixels becomes about 4 um, it is very difficult to reduce pixel size any more without sacrificing performance such as sensitivity.
However, the resolution of the objective lens can be increased to about 1 um depending on use. That is, the conventional electronic endoscope cannot take advantage of the high resolution possessed by an optical system, thus making it difficult to achieve high resolution.
The present invention has been made in view of such circumstance. It is an object of the present invention to provide an optical device and an endoscope using the same which is capable of acquiring a two-dimensional image with high resolution without employing an expensive CCD.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.